High speed blower



Sept 29, 1931.

F. w. KENNDVY HIGH SPEED BLOWER Filed Dec. 23, Y1924 Patented Sept. 29,1931 UNITED STATES PATENT OFFICE rnANx w. KENNEDY, or TnEN'mN, NawJERSEY, AssTGNon. 'ro DE Lavar. STEAM: 'runnnm courANY, or raENroN, NEWJERSEY, 'A conrona'rroN or Nnw amsn-Y v HIGH' SPEED BLGWEB Applicationled December 23, 1924. Serial No. 757,585.

In wheels for high speed blowers comprising a wheel hub, side plate andconnecting steel vanes, it has been found essential to make the vanes ofcomparatively thin sheet steel,

in order to secure lightness, as heavy vanes would result in animpracticably great stress both on the vanes and on the hub and sideplates. In the usual construction these vanes are provided with sidelianges (so as to have 30 an approximately trough-shaped or shallowlll-shaped form in cross-section), which anges are riveted respectivelyto the hub and the side plate.

I have found that it is highly desirable to te so shape the vanes that,as they approach the periphery of the wheel, they will extend backwardrelatively to the direction of rotation of the wheel at a pronouncedangle to the radius-at least in excess of twenty degrees. The au mosteicient shape is that of a simple curve extending throughout most of itslength, and particularly as it approaches the peripheral outlet, at anangle more or less approximating forty-five degrees to the radius. Thisconstruction, however, has been found to be wholly impracticable withvanes of sheet steel, especially with wide wheels rotating at a highrate of s eed, the vanes having a strong tendency to end at the outletdue to centrifugal force. For this reason, it has been found necessarythat, as they approach the outlet, the vanes shall be curved toward theradius of the wheel on a center outside the periphery of the wheel, sothat their outer ends extend radially to the wheel, or nearly so. Thebest compromise construction is that of a compound curve which, near theinlet, is at a pronounced angle (say sixty degrees) to the radius andwhich is thence curved outward toward the outlet at a rapidly diminishling angle to the radius so that its rear face is convex in itslongitudinal direction of extension, until, as it approaches the outlet,it extends radially, or nearly so, as above'stated. This gives areasonably strong construction, but only at the sacrifice ofeiiiciency.` The construction is also relatively expensive.

have found that it is possible to (provide n' wheels-even those havinggreat wi th and high velocity-with vanes shaped to give the highesteiliciency and at the same time avoid the stresses above mentioned andthe danger of bending at the outlet, and provide a construction that isysubstantially cheaperv lto manufacture. y

My new vane comprises a relativel l, thick vane having thehereinbefore'speciiizd desix-able direction of extension relativelyl tothe wheel, the thickness of thevane being suiiicient to allow rivets toextend entirely through the same from edge to edge, so that a singlerivet may extend through the wheel hub, the vane and the side-plate. Thevanes are preferably unlianged, as flanges are unnecessary forreinforcement or to provide rivet-'engaging means. yA constructionembodying my invention is, however, impracticable if the vanes are madeof steel, because of their excessive weight and resultant greatstresses, as above explained. v i

I find, however, that if the metal duralumin `be substituted for steel,it will afford the necessary strength, being almost as strong as steel,and being so light that the stresses resulting will not be greater thanin the old structure.

With vanes shaped as above described to give the highest efiiciency, thetendency to bend at the outlet due to the great centrifugal force willbe successfully resisted due tothe thickness of the vanes.

A preferred embodiment of my invention is shown in the drawings, inwhich- Fig. 1 is a cross-sectional view through half the wheel.

Fig. 2 is a face View of Fig. 1 with side plate omitted. x c

Fig. 3is a detail ksection on lineB--B of Fig.2. c i y.

Between the hub a and theside platefb extend the vanes c., It willbeobserved that the directiony of extensionof the vanesas they approachthe o utlet is backwardl relative to the direction of rotation ofthefwheel and,

at a pronounced angle (approximating fortyfve degrees) to the radiusofthe Wheel.` The vane, preferably substantially throughout its length,and particularly 4the outer part thereof, is curved on a lcenter within`the pe riphery of the wheel, its rear face being concave in itslongitudinal direction of extension; and, preferably throughout itslength, and particularly along its outer paitextentls at an angle to thewheels radins which does not vary greatly from forty-five degrees. Insome cases, however, said center of curvature would be outside.of thewheels periphery. The angle of extension of the vane, to the radius ofthe wheel, and even the angle of extension of the outlet end ortionthereof, may be varied from the ang e specified; but the angle ofextension of the outlet end of the vane to the radius of the wheelshould not be less than about twentv degrees. It is not necessar thatthe vane should becurved throughout its length, although that ispreferable, as it may extend for part of its length in a straight line,or even may be reversely curved, provided the direction of extension ofits outlet end portion is as specified. How ever, the most eicient shapeis that illustrated, wherein the rear face of the vane is substantiallcontinuously concave in its longitudinal direction of extension.

Rivets d extend through the hub, vane and side plate, as shown.

The vanes may be lightened by cormg out the metal, as shown at e,between the rivets.

Duralumin is a commercial alloy known in commerce only by that name. Itsrecise composition is not a matter of general now]- edgc, but it isbelieved to be an alloy of aluminum, copper, manganese and magnesium.

In place of duralumin, there may be used lany other aluminum compositionor allo that, while of a lightness comparable wit duralumin, alsopossesses suicient strength. The construction herein described is deemedto be novel, independently of the composition of the vanes, in highspeed blowers, but` unless such construction comprises vanes made ofduralumin or its equivalents, it is impracticable or inoperative. Itwill be understood that Il do not claim as my invention the meresubstitution of duralumin or its uivalent for steel, but claim only thedescri ed construction in which the vanes are made of such metal alloy;the two features of construction and composition cooperating to attainthe objects and secure the advantages herein set forth; it beingunderstood, also, that if the vanes should be made of steel or theordinary alloys thereof the construction would be impracticable as beintoo heavy, while most other materials as light as duralumin wouldproduce a construction that would be impracticable as being too weak.

Having now fully described my invention, what I claim and desire toprotect by Letters Patent is:

1. A blower wheel for high speed blowers comprising a hub, a side plate,duralumin vanes extending between them, and rivets uniting the vanes tothe hub and side plate,

vanes adjacent the rivets being solid and substantially thicker than theShanks of the rivets and the rivets which unite a vane to the hub andside plate extending through all three members and from edge to edge andbetween the faces of the vane, the outlet end portion of the vaneextending backward relative to the direction of rotation of the wheel atan angle not less than twenty degrees to the radius of the wheel.

2. A blower wheel for high speed blowers comprising a hub, a side plate,duraluniin vanes extending between them, and rivets uniting the vanes tothe hub and side plate, the vanes adjacent the rivets being solid andsubstantially thicker than the Shanks of the rivets and the rivets whichunite a vane to the hub and side plate extending through all threemembers and from edge to edge and between the faces of the vane, therear face of the outlet end portion of the vane being concave in itslongitudinal extension.

3. A blower wheel for high speed blowers comprising a hub, a side plate,duralumin vanes extending between them, and rivets uniting the vanes tothe hub and side plate, the vanes adjacent the rivets being solid andsubstantially thicker than the Shanks of the rivets and the rivets whichunite a vane to the hub and side plate extending through all threemembers and from edge to edge and between the faces of the vane, theoutlet end portion of the vane being curved on a radius whose center iswithin the periphery of the wheel.

4. A blower wheel for high speed blowers comprising a hub, a side plate,duralumin vanes extending between them, and rivets uniting the vanes tothe hub and side late, the vanes adjacent the rivets being soli andsubstantially thicker than the Shanks of the rivets and the rivets whichunite a vane to the hub and side plate extending through all threemembers and from edge to edge and between the faces of the vane, thevane being curved throu hout the major part of its length in sucdirectionthat its rear face is concave in its longitudinal extension.

5. A blower Wheel for high speed blowers comprising a hub, a side plate,duraluminv vanes extending between them, and rivets uniting the vanes tothe hub and side late, the vanes adjacent the rivets being solid andsubstantially thicker than the shanks of the rivets and the rivets whichunite a vane to the hub and side plate extending through all threemembers and from edge to edge and between the faces of the vane, thevane being curved throughout the major part of its length on a radiuswhose center is within the periphery of the wheel.

6. A blower wheel for high speed blowers comprising a hub, a side plate,duralumin vanes extending between them, and rivets uniting the vanes tothe hub and side plate,

llt

the vanes being substantially thicker than the shanks of the rlvets andthe rivets which unite a vane tothe hub and side plate extending throughall three members and from edge to edge and bet-Ween the fa'ces of thevane, the vanes being cored between adjacent rivets and at their outletportion extending backward relative to the direction of rotation of theWheel.

7 In a compressor wheel, the combination with the wheel discs, of hollowblades bev tween the discs, said blades having transpressor wheelscomprising cooperatingr Wall' portions arranged in spaced relationship,spacing members between the wall portions and secured thereto, andattaching members projecting from the ends of the spacing inembers.

In testimony of which invention, I have hereunto set my hand, atTrenton, New Jersey, on this 19th day of December, 1924.

FRANK W. KENNEDY.

